Study Notes on Atmospheric Carbon Dioxide and Particulate Matter

A. Lightning Strikes
- Converts atmospheric nitrogen (N₂) into nitrogen oxides (NOx).
B. Forest Fires
- Produce carbon dioxide (CO₂), particulate matter (PM), and nitrogen oxides (NOx).
- Result from the combustion of biomass.
C. Plants
- Especially coniferous trees release terpenes and other compounds.
D. Volcanoes
- Emit sulfur dioxide (SO₂), carbon dioxide (CO₂), nitrogen oxides (NOx), and PM.

Note: Not specifically differentiated as biogenic sources in the given transcript.
A. Respiration
- All living organisms, including plants, release CO₂ through aerobic respiration.
B. Natural Particulate Matter (PM) Sources
- Includes sea salt, pollen, and ash from natural events.
C. Aerosol Decomposition
- Organic matter undergoes aerobic decomposition, releasing various compounds.
D. Anaerobic Decomposition
- Organic matter breakdown in oxygen-poor environments, contributing to biogenic emissions.

Definition: PM refers to solid or liquid particles suspended in the air.
A. PM10
- Particles with a diameter of less than 10 micrometers.
  - Comprised of particles or droplets such as dust, pollen, ash, or mold.
  - Too small to be filtered by the nose hairs and trachea cilia, allowing them to enter deeper into the respiratory tract.
B. PM2.5
- Particles with a diameter of less than 2.5 micrometers.
  - Primarily generated from combustion processes.
  - More likely to penetrate deep into the lungs due to smaller size.
  - Significant health implications:
    - Associated with chronic bronchitis and lung cancer due to their ability to travel deeper into the respiratory tract.